All com.google.android.gms libraries must use the exact same version
specification (mixing versions can lead to runtime crashes). Found
versions 8.3.0, 8.1.0. Examples include
com.google.android.gms:play-services-base:8.3.0 and
com.google.android.gms:play-services-measurement:8.1.0 There are some
combinations of libraries, or tools and libraries, that are
incompatible, or can lead to bugs. One such incompatibility is
compiling with a version of the Android support libraries that is not
the latest version (or in particular, a version lower than your
targetSdkVersion.)